仿SQLPLUS

实现sqlplus的功能，代码如下：
import java.sql.*;
import java.io.*;

public class SQLTools{
   public static void main(String[] args){
    StringBuffer info=new StringBuffer();
    info.append("-------read me--------\n");
    info.append("commit;---excute con.commit();---\n");
    info.append("rollback;---excute con.rollback();---\n");
    info.append("sqlString;---excute sql command;---\n");
    info.append("quit;---excute con.commit() and quit program---\n");
    info.append("-----------end-----------\n");
    System.out.println(info.toString());
    Connection con= null;
    while((con=getConnection())==null){}
    try{
       con.setAutoCommit(false);
       StringBuffer sb=new StringBuffer();
       String cmd="";
       boolean flag=true;
       int c=0;
       String message="";
       while(flag){
        
          if(c++==0){
            message="SQLTools-> ";
             }else{
        message=c+"-> ";
              }
          sb.append(prompt(message));
          cmd=sb.toString().trim();
          if(cmd.endsWith(";")){
             String sql=cmd.substring(0,cmd.length()-1);

             if("quit".equals(sql)){
           flag=false;
            con.commit();
             sb=new StringBuffer();
            c=0;
              }else if("commit".equals(sql)){
            con.commit();
             sb=new StringBuffer();
            c=0;
        }else if("rollback".equals(sql)){
            con.rollback();
            sb=new StringBuffer();
            c=0;
        }else{
            System.out.println(sql);
            execute(sql,con);
            sb=new StringBuffer();
            c=0;
        }
          }
       }
  
    }catch(Exception e){System.out.println("rollback");
                try{if(con!=null)con.rollback();
                   }catch(Exception e3){e3.printStackTrace();}
               }
    finally{JdbcUtil.release(con);}
   }
   public static Connection getConnection(){
  
    String message="url:\n";
    String url=prompt(message);
    message="username:\n";
    String username=prompt(message);
    message="password:\n";
    String pwd=prompt(message);
    Connection con=null;
    try{
       con=DriverManager.getConnection(url,username,pwd);
    }catch(Exception e){System.out.println("->connection failed");}
    return con;
   }
   public static String prompt(String message){
    BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
    System.out.println(message);
    String input="";
    try{
       input=in.readLine();
    }catch(Exception e){e.printStackTrace();}
    return input;
   }
   public static void execute(String sql,Connection con)throws Exception{
    int c=0;
    Statement stmt=null;
    ResultSet rs=null;
    try{
       stmt=con.createStatement();
       if(stmt.execute(sql)){
          rs=stmt.getResultSet();
          JdbcUtil.printRs(rs);
       }else{
          c=stmt.getUpdateCount();
          System.out.println("update succefully!"+c);
       }
    }catch(Exception e){System.out.println("database manipulation failed!");}
    finally{JdbcUtil.release(rs,stmt,null);}

   }
}